Question related to roll crimp -How much is enough

sigarmsp226

Was loading 30-06 ammo for my bolt action deer rifle this weekend and the dies I have are roll crimp design. The RCBS instructions that came with the die set identifies that I should take a sized, primed, ready to load cartridge and place it on the charging handle in the shell holder and raise it to its highest level. Then take the seating/crimping die and screw it down until it makes contact with the shell shoulder. Lower the charge handle and then trun the die 1/8 to 1 full turn downard based upon the amount of crimp you desire. My bullet does not have a canulure so can someone tell me about how much roll crimp is enough - 1/8 turn, 1/4 turn, 1/2 turn, etc.... I loaded 10 rounds at 1/4 turn down but can go back and add more if I should.....Any comments/help is greatly appreciated.....Thanks Mark

PA Shootist

I'd suggest essentially no roll crimp for bullet without cannelure. The attempt to roll crimp might make the case neck at the mouth sort of grab into the bullet and push the whole shoulder back, bulging and deforming the case at the shoulder. The case now distorted might not even feed into the chamber. Rather a slight taper crimp, or perhaps a squeeze collet crimp like the Lee "Factory Crimp" die gives, and not overdoing either of those. In most rifles not too much crimp is necessary, if the interior of the neck is sized tightly enough to grip the bullet firmly. I try to use just enough to prevent the bullet moving forward out of the case mouth under recoil, or the bullet being pushed back into the case when handling. Tubular magazines may require more; for those rifles a cannelure or crimp groove is preferred.

If there is a crimping groove or cannelure, the crimp should still not be overdone. With this process trim-to length is critical, all cases should be exactly the same length for uniform crimp.

sigarmsp226

Did I make a mistake buying roll crimp dies? SHould I have bought or should I buy a taper crimp die for my bolt action rifles?.....Mark

elubsme

I totally agree with Paul. I've been using roll crimp dies since Pop bought a set of .32 Special dies for me back in 1958[;)]. They work fine, just don't over crimp the bullets or they will bulge the shoulder as Paul says. Hey Paul, there are some Nusses on my Mother's side of the family, She grew up in Montgomery, Pa. Are we distant cousins? Eddie

PA Shootist

I think most dies are of the type that will roll crimp, if you adjust them so. I adjust mine to not crimp by raising the sized and neck-expanded trimmed case fully in the press, then screw the crimping/seating die down until the crimp shoulder just touches the case neck, and go no further. I adjust the seating depth second and separately. This might squeeze the case mouth a tiny bit, but won't roll the brass into the bullet as you seat. If you measured with a micrometer, the very end might be a thousandth or so smaller than just behind the case mouth, maximum. If there is a crimp, it isn't much and didn't roll in much. The interior of the case neck is still parallel to and in uniform contact with the bullet sides, not bulged or distorted away, and the shoulder isn't going to push back or distort. You can see the necessity of exact case trim-to length for this to work correctly every time. The collet squeeze dies such as the Lee factory crimp die are less sensitive to any small variations in case length, though best practice is probably still uniform trim-to dimensions.

sigarmsp226

So is it safe to say that the bullet is held in the cartridge strictly by friction and pressure between the two. Thanks again for your time and comments. Still have a lot to learn....Mark

wsfiredude

Mark,

They have been mentioned already, but the factory crimp dies produced by Lee work splendidly.

A good many seating dies are set up to crimp as well. It's best to seat your bullets first, then crimp in a seperate operation instead of trying to do both at the same time.

Tailgunner1954

quote:Originally posted by sigarmsp226
So is it safe to say that the bullet is held in the cartridge strictly by friction and pressure between the two. Thanks again for your time and comments. Still have a lot to learn....Mark

Correct.
Most seating dies will provide a roll crimp, IF the operator wants to set them up that way.
I don't crimp 30-06 for either my bolt gun or my Garand (the only rifle rounds I do crimp are for tube mags and things that kick harder than a 375H&H).

To set the seat/crimp die, 1) raise a sized case in the shell holder, screw the die down until you feel it hit the case mouth. Now raise (un-screw) the die 1 full turn (if you are not going to crimp, you can lock it there). 2) Lower the case and set a bullet in place, raise the ram and adjust the seating stem to get the OAL you desire (hint, one full turn of the seating stem will move the bullet about .050). Again if you are not crimping, you can lock it into place now.

IF a crimp is desired, (and the bullets canalure lines up with the case mouth) 3) raise the seating stem 3-4 full turns and lower the die body until you feel it hit the case mouth. Now, lowering the die no more than 1/8 turn at a time, adjust the crimp until you can just detect a slight turn in of the case mouth (to much crimp can actually loosen the bullet and/or bulge the shoulder). Lock your die in place.
4) lower the seating stem until it's in firm contact with the seated/crimped bullet and lock it in place.

sigarmsp226

Thanks guys for the detail and also restating what had earlier be indicated. Takes me several times, sometimes, to understand and get the point. I will follow to the "T" the suggestions and I am going to order a Lee Factory Crimp Die for my rifle...

Reloader44mag guided me in that direction when I was buying my pistol dies and I bought the Lee 4 die set. Loading on that side has worked very well.

I do appreciate your comments, suggestions, and level of detail. Regards to all.....Mark

sigarmsp226

Guys - I received my package today that contained my Lee Factory Crimp dies and man are they easy to use and provide a crimp that looks exactly like the crimp on many of my factory rounds. Cost - $9.40 per caliber... I bought one for my 223, 308, and 30-06....I followed the directions and crimped 50 rounds of 223 and 10 rounds of 30-06 in less than 15 minutes.

Thanks again guys for your guidance related to this simple solution....Mark

wsfiredude

quote:Originally posted by sigarmsp226
Guys - I received my package today that contained my Lee Factory Crimp dies and man are they easy to use and provide a crimp that looks exactly like the crimp on many of my factory rounds. Cost - $9.40 per caliber... I bought one for my 223, 308, and 30-06....I followed the directions and crimped 50 rounds of 223 and 10 rounds of 30-06 in less than 15 minutes.

Thanks again guys for your guidance related to this simple solution....Mark


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